It is also worth pointing out that the American posters are only referring to discretionary vacation time. Most US companies have eight or so fixed holidays in addition.
In Europe we very rarely count public holidays in vacation time - you can generally assume that most of the numbers listed in this discussion from Europeans is discretionary vacation time that comes in addition to 8 (UK) to 15 (Finland) or so public holidays (though not all countries mandate time off or time in lieu for public holidays).
I'm in the UK, and have 25 days discretionary holiday, plus 8 days of public holidays
28 is the legal minimum in the UK, however that includes bank holidays. You probably actually have 36 including bank holidays